Ultrasonic surgical instruments

ABSTRACT

An ultrasonic surgical blade comprises a solid blade body defining an axis. The solid blade body comprises a first length, a proximal end, and a distal end. The solid blade body is configured to acoustically couple to an ultrasonic transducer. The ultrasonic surgical blade further comprises a treatment region and a first edge at the distal end of the solid blade body. The ultrasonic surgical blade comprises an inner concave surface. The inner concave surface comprises a cavity extending proximally from the distal end of the solid blade body along the axis. The cavity terminates at a proximal end of the inner concave surface. The inner concave surface is configured to cause fluid droplets to converge along the axis when the fluid droplets collide with the inner concave surface to enhance visibility of a surgical site.

CROSS REFERENCE TO RELATED APPLICATIONS

This application is a continuation application claiming priority under35 U.S. C. § 120 to U.S. patent application Ser. No. 11/881,645,entitled ULTRASONIC SURGICAL INSTRUMENTS, filed Jul. 27, 2007, now U.S.Pat. No. 8,882,791, the entire disclosure of which is herebyincorporated by reference herein.

The subject application is related to commonly-owned U.S. patentapplication Ser. No. 11/881,636, filed on Jul. 27, 2007, now U.S. Pat.No. 8,348,967, the disclosure of which is hereby incorporated byreference in its entirety, the application being respectively entitledULTRASONIC SURGICAL INSTRUMENTS.

BACKGROUND

Ultrasonic instruments, including both hollow core and solid coreinstruments, are used for the safe and effective treatment of manymedical conditions. Ultrasonic instruments, and particularly solid coreultrasonic instruments, are advantageous because they may be used to cutand/or coagulate tissue using energy in the form of mechanicalvibrations transmitted to a surgical end effector at ultrasonicfrequencies. Ultrasonic vibrations, when transmitted to organic tissueat suitable energy levels and using a suitable end effector, may be usedto cut, dissect, or coagulate tissue or elevate or separate muscletissue off bone. Ultrasonic instruments utilizing solid core technologyare particularly advantageous because of the amount of ultrasonic energythat may be transmitted from the ultrasonic transducer, through anultrasonic transmission waveguide, to the surgical end effector. Suchinstruments may be used for open procedures or minimally invasiveprocedures, such as endoscopic or laparoscopic procedures, wherein theend effector is passed through a trocar to reach the surgical site.

Activating or exciting the single or multiple element end effector(e.g., cutting blade, ball coagulator) of such instruments at ultrasonicfrequencies induces longitudinal, transverse, or torsional vibratorymovement that generates localized heat within adjacent tissue,facilitating both cutting and coagulating. Because of the nature ofultrasonic instruments, a particular ultrasonically actuated endeffector may be designed to perform numerous functions, including, forexample, cutting and coagulating.

Ultrasonic vibration is induced in the surgical end effector byelectrically exciting a transducer, for example. The transducer may beconstructed of one or more piezoelectric or magnetostrictive elements inthe instrument hand piece. Vibrations generated by the transducersection are transmitted to the surgical end effector via an ultrasonicwaveguide extending from the transducer section to the surgical endeffector. The waveguides and end effectors are most preferably designedto resonate at the same frequency as the transducer. When an endeffector is attached to a transducer the overall system frequency may bethe same frequency as the transducer itself.

The transducer and the end effector may be designed to resonate at twodifferent frequencies and when joined or coupled may resonate at a thirdfrequency. The zero-to-peak amplitude of the longitudinal ultrasonicvibration at the tip, d, of the end effector behaves as a simplesinusoid at the resonant frequency as given by:d=A sin(ωt)where:ω=the radian frequency which equals 2π times the cyclic frequency, f;andA=the zero-to-peak amplitude.The longitudinal excursion is defined as the peak-to-peak (p-t-p)amplitude, which is just twice the amplitude of the sine wave or 2 A.

Solid core ultrasonic surgical instruments may be divided into twotypes, single element end effector devices and multiple-element endeffectors. Single element end effector devices include instruments suchas scalpels (e.g., blades, sharp hook blades, dissecting hook blades,curved blades) and ball coagulators. Single-element end effectorinstruments have limited ability to apply blade-to-tissue pressure whenthe tissue is soft and loosely supported. Substantial pressure may benecessary to effectively couple ultrasonic energy to the tissue. Theinability of a single-element end effector to grasp the tissue resultsin a further inability to fully coapt tissue surfaces while applyingultrasonic energy, leading to less-than-desired hemostasis and tissuejoining. The use of multiple-element end effectors such as clampingcoagulators includes a mechanism to press tissue against an ultrasonicblade that can overcome these deficiencies.

Ultrasonic clamp coagulators or clamped coagulating shears provide animproved ultrasonic surgical instrument for cutting/coagulating tissue,particularly loose and unsupported tissue, wherein the ultrasonic bladeis employed in conjunction with a clamp for applying a compressive orbiasing force to the tissue, whereby faster coagulation and cutting ofthe tissue.

As the distal end of the end effector, or more particularly, the blade,cuts through or coagulates tissue it comes into contact with fluid(e.g., blood, tissue particles). When the distal end of the bladecontacts this fluid, a fine mist in the form of a diverging plume offluid particles may emanate from the distal end of the blade. This plumeof mist may limit visibility at the surgical site. It would be desirableto provide an ultrasonic instrument which reduces the plume of mistemanating from the distal end of the end effector.

SUMMARY

In one general aspect, the various embodiments are directed to a anultrasonic blade with mist reducing features. A solid blade body of theultrasonic blade may define an axis, and comprise a first length, aproximal end, and a distal end. The solid blade body may be configuredto acoustically couple to an ultrasonic transducer. The ultrasonicsurgical blade may further comprise a treatment region and a first edgeat the distal end of the solid blade body. The ultrasonic surgical blademay comprise an inner concave surface. The inner concave surface maycomprise a cavity extending proximally from the distal end of the solidblade body along the axis. The cavity may terminate at a proximal end ofthe inner concave surface. The cavity may comprise a second lengthbetween the first edge and the proximal end. The first length may besubstantially longer than the second length. The inner concave surfacemay be configured to cause fluid droplets to converge along the axiswhen the fluid droplets collide with the inner concave surface toenhance visibility of a surgical site.

FIGURES

The novel features of the various embodiments are set forth withparticularity in the appended claims. The various embodiments, however,both as to organization and methods of operation, may best be understoodby reference to the following description, taken in conjunction with theaccompanying drawings as follows.

FIG. 1A illustrates one embodiment of an ultrasonic system comprising asingle element end effector.

FIG. 1B illustrates one embodiment of an ultrasonic system comprising amulti-element end effector.

FIG. 2 illustrates one embodiment of a connection union/joint for anultrasonic instrument.

FIG. 3A illustrates an exploded perspective view of one embodiment of asingle element end effector ultrasonic surgical instrument that may becoupled to the ultrasonic system illustrated in FIG. 1A.

FIG. 3B illustrates one embodiment of a clamp coagulator comprising amulti-element end effector as shown in FIG. 1B.

FIG. 3C illustrates a perspective view of the multi-element end effectoras shown in FIGS. 1B and 3B.

FIGS. 4-6 illustrate one embodiment of an ultrasonic blade, where:

FIG. 4 is a side view of one embodiment of an ultrasonic blade;

FIG. 5 is a cross-sectional view of the ultrasonic blade taken alongline 5-5 in FIG. 4; and

FIG. 6 is a perspective view of the ultrasonic blade shown in FIG. 4.

FIGS. 7-9 illustrate various embodiments of the ultrasonic blade, where:

FIG. 7 is a side view of one embodiment of an ultrasonic blade;

FIG. 8 is a cross-sectional view of the ultrasonic blade taken alongline 8-8 in FIG. 7; and

FIG. 9 is a perspective view of the ultrasonic blade shown in FIG. 7.

FIGS. 10-12 illustrate one embodiment of the ultrasonic blade, where:

FIG. 10 is a side view of one embodiment of an ultrasonic blade;

FIG. 11 is a cross-sectional view of the ultrasonic blade taken alongline 11-11 in FIG. 10; and

FIG. 12 is a perspective view of the ultrasonic blade shown in FIG. 10.

FIGS. 13A-B illustrate various embodiments of an ultrasonic blade,where:

FIG. 13A is a side view of an ultrasonic blade with a convex blade tipdepicting a divergent plume mist; and

FIG. 13B is a detail view of the divergent jet of fluid mist.

FIGS. 14A-B illustrate various embodiments of an ultrasonic blade,where:

FIG. 14A is a side view of an ultrasonic blade with a tapered concavesurface formed at a distal end of the blade depicting a convergence ofthe fluid leaving the blade tip; and

FIG. 14B is a detail view of the convergent jet of fluid mist.

FIGS. 15A-D illustrate various embodiments of an ultrasonic blade,where:

FIG. 15A is a side view of an ultrasonic blade with at least a portionof the ultrasonic blade coated with at least one layer of a materialwhich may allow the fluid to form globules on the surface of thematerial; and

FIG. 15B is cross-sectional view of the ultrasonic blade taken alongline B-B in FIG. 15A.

FIG. 15C is a detailed view of the ultrasonic blade of FIG. 15A.

FIG. 15D illustrates a contact angle between a droplet and the surfaceof the ultrasonic blade of FIG. 15A.

FIGS. 16-17 illustrate various embodiments of an ultrasonic blade,where:

FIG. 16 is a side view of an ultrasonic blade with portions of the bladecoated with more than one material to provide an electric charge to theblade tip; and

FIG. 17 is cross-sectional view of the ultrasonic blade taken along line17-17 in FIG. 16.

FIGS. 18-19 illustrate various embodiments of an ultrasonic blade,where:

FIG. 18 is a side view of an ultrasonic blade with a longitudinallyextending bore; and

FIG. 19 is cross-sectional view of the ultrasonic blade taken along line19-19 in FIG. 18.

FIG. 20 is a side view of an ultrasonic blade with a convex portionwithin a tapered concave surface thereof.

FIG. 21-22 illustrate various embodiments of an ultrasonic blade, where:

FIG. 21 is a side view of an ultrasonic blade with a tapered concavesurface extending into the blade body asymmetrically.

FIG. 22 is a cross-sectional view of the ultrasonic blade taken alongline 22-22 in FIG. 21.

FIG. 23 is a perspective view of an asymmetric ultrasonic bladecomprising a tapered concave surface extending inwardly into the bladebody.

DESCRIPTION

Before explaining the various embodiments in detail, it should be notedthat the embodiments are not limited in its application or use to thedetails of construction and arrangement of parts illustrated in theaccompanying drawings and description. The illustrative embodiments maybe implemented or incorporated in other embodiments, variations andmodifications, and may be practiced or carried out in various ways. Forexample, the surgical instruments and blade configurations disclosedbelow are illustrative only and not meant to limit the scope orapplication thereof. Furthermore, unless otherwise indicated, the termsand expressions employed herein have been chosen for the purpose ofdescribing the illustrative embodiments for the convenience of thereader and are not to limit the scope thereof.

The various embodiments relate, in general, to ultrasonic blades for usein surgical instruments and, more particularly, to ultrasonic bladescomprising mist reducing features as described herein. The variousembodiments relate, in general, to ultrasonic blades and instruments toimprove visibility of the surgical site during surgery by reducing themist plume created by fluid particles colliding with a distal end of anactivated ultrasonic blade. Visibility of the surgical site may beimproved through the mist reducing features of the ultrasonic bladeswhich may comprise a tapered concave surface formed at the distal end ofthe blade, a tip coating, a lumen fluidically coupled to a sprayingmechanism, a material to hold an electric charge, or any combinationthereof. The term “tapered concave surface” is defined as a concavesurface formed at a distal end of the blade that is tapered inwardlyfrom its distal end to its proximal end in the direction indicated byarrow B, various embodiments of which are shown in FIGS. 4-23. A varietyof different blade configurations are disclosed which may be useful forboth open and laparoscopic applications.

Examples of ultrasonic surgical instruments are disclosed in U.S. Pat.Nos. 5,322,055 and 5,954,736 and in combination with ultrasonic bladesand surgical instruments disclosed in U.S. Pat. Nos. 6,309,400 B2,6,278,218 B1, 6,283,981 B1, and 6,325,811 B1, for example, areincorporated herein by reference in their entirety. These referencesdisclose ultrasonic surgical instruments and blade configurations wherea longitudinal mode of the blade is excited. Because of asymmetry orasymmetries, ultrasonic blades also may exhibit transverse and/ortorsional motion where the characteristic “wavelength” of thisnon-longitudinal motion is generally less than that of the generallongitudinal motion of the blade and its extender portion. Therefore,the wave shape of the non-longitudinal motion will present nodalpositions of transverse/torsional motion along the tissue effector whilethe net motion of the active blade along its tissue effector is non-zero(i.e., will have at least longitudinal motion along the length extendingfrom its distal end, an antinode of longitudinal motion, to the firstnodal position of longitudinal motion that is proximal to the tissueeffector portion).

Certain embodiments will now be described to provide an overallunderstanding of the principles of the structure, function, manufacture,and use of the devices and methods disclosed herein. One or moreexamples of these embodiments are illustrated in the accompanyingdrawings. Those of ordinary skill in the art will understand that thedevices and methods specifically described herein and illustrated in theaccompanying drawings are non-limiting embodiments and that the scope ofthe various embodiments is defined solely by the claims. The featuresillustrated or described in connection with one embodiment may becombined with the features of other embodiments. Such modifications andvariations are intended to be included within the scope of the claims.

FIG. 1A illustrates one embodiment of an ultrasonic system 10 comprisinga single element end effector. One embodiment of the ultrasonic system10 comprises an ultrasonic signal generator 12 coupled to an ultrasonictransducer 14, a hand piece assembly 60 comprising a hand piece housing16, and an ultrasonically actuatable single element end effector orultrasonically actuatable blade 50. The ultrasonic transducer 14, whichis known as a “Langevin stack”, generally includes a transductionportion 18, a first resonator portion or end-bell 20, and a secondresonator portion or fore-bell 22, and ancillary components. The totalconstruction of these components is a resonator. The ultrasonictransducer 14 is preferably an integral number of one-half systemwavelengths (nλ/2; where “n” is any positive integer; e.g., n=1, 2, 3 .. . ) in length as will be described in more detail later. An acousticassembly 24 includes the ultrasonic transducer 14, a nose cone 26, avelocity transformer 28, and a surface 30.

It will be appreciated that the terms “proximal” and “distal” are usedherein with reference to a clinician gripping the hand piece assembly60. Thus, the blade 50 is distal with respect to the more proximal handpiece assembly 60. It will be further appreciated that, for convenienceand clarity, spatial terms such as “top” and “bottom” also are usedherein with respect to the clinician gripping the hand piece assembly60. However, surgical instruments are used in many orientations andpositions, and these terms are not intended to be limiting and absolute.

The distal end of the end-bell 20 is connected to the proximal end ofthe transduction portion 18, and the proximal end of the fore-bell 22 isconnected to the distal end of the transduction portion 18. Thefore-bell 22 and the end-bell 20 have a length determined by a number ofvariables, including the thickness of the transduction portion 18, thedensity and modulus of elasticity of the material used to manufacturethe end-bell 20 and the fore-bell 22, and the resonant frequency of theultrasonic transducer 14. The fore-bell 22 may be tapered inwardly fromits proximal end to its distal end to amplify the ultrasonic vibrationamplitude as the velocity transformer 28, or alternately may have noamplification. A suitable vibrational frequency range may be about 20 Hzto 120 kHz and a well-suited vibrational frequency range may be about30-100 kHz. A suitable operational vibrational frequency may beapproximately 55.5 kHz, for example.

Piezoelectric elements 32 may be fabricated from any suitable material,such as, for example, lead zirconate-titanate, lead meta-niobate, leadtitanate, barium titanate, or other piezoelectric ceramic material. Eachof positive electrodes 34, negative electrodes 36, and the piezoelectricelements 32 has a bore extending through the center. The positive andnegative electrodes 34 and 36 are electrically coupled to wires 38 and40, respectively. The wires 38 and 40 are encased within a cable 42 andelectrically connectable to the ultrasonic signal generator 12 of theultrasonic system 10.

The ultrasonic transducer 14 of the acoustic assembly 24 converts theelectrical signal from the ultrasonic signal generator 12 intomechanical energy that results in primarily a standing acoustic wave oflongitudinal vibratory motion of the ultrasonic transducer 14 and theend effector 50 at ultrasonic frequencies. In another embodiment, thevibratory motion of the ultrasonic transducer may act in a differentdirection. For example, the vibratory motion may comprise a locallongitudinal component of a more complicated motion of the tip of theultrasonic system 10. A suitable generator is available as model numberGEN04, from Ethicon Endo-Surgery, Inc., Cincinnati, Ohio. When theacoustic assembly 24 is energized, a vibratory motion standing wave isgenerated through the acoustic assembly 24. The ultrasonic system 10 isdesigned to operate at a resonance such that an acoustic standing wavepattern of predetermined amplitude is produced. The amplitude of thevibratory motion at any point along the acoustic assembly 24 dependsupon the location along the acoustic assembly 24 at which the vibratorymotion is measured. A minimum or zero crossing in the vibratory motionstanding wave is generally referred to as a node (i.e., where motion isminimal), and a local absolute value maximum or peak in the standingwave is generally referred to as an anti-node (i.e., where local motionis maximal). The distance between an anti-node and its nearest node isone-quarter wavelength (λ/4).

The wires 38 and 40 transmit an electrical signal from the ultrasonicsignal generator 12 to the positive electrodes 34 and the negativeelectrodes 36. The piezoelectric elements 32 are energized by theelectrical signal supplied from the ultrasonic signal generator 12 inresponse to an actuator 44, such as a foot switch, for example, toproduce an acoustic standing wave in the acoustic assembly 24. Theelectrical signal causes disturbances in the piezoelectric elements 32in the form of repeated small displacements resulting in largealternating compression and tension forces within the material. Therepeated small displacements cause the piezoelectric elements 32 toexpand and contract in a continuous manner along the axis of the voltagegradient, producing longitudinal waves of ultrasonic energy. Theultrasonic energy is transmitted through the acoustic assembly 24 to thesingle element end effector such as the blade 50 via a transmissioncomponent or an ultrasonic transmission waveguide 104.

In order for the acoustic assembly 24 to deliver energy to the singleelement end effector 50, all components of the acoustic assembly 24 mustbe acoustically coupled to the blade 50. The distal end of theultrasonic transducer 14 may be acoustically coupled at the surface 30to the proximal end of the ultrasonic transmission waveguide 104 by athreaded connection such as a stud 48.

The components of the acoustic assembly 24 are preferably acousticallytuned such that the length of any assembly is an integral number ofone-half wavelengths (nλ/2), where the wavelength λ is the wavelength ofa pre-selected or operating longitudinal vibration drive frequency f_(d)of the acoustic assembly 24. It is also contemplated that the acousticassembly 24 may incorporate any suitable arrangement of acousticelements.

The blade 50 may have a length substantially equal to an integralmultiple of one-half system wavelengths (nλ/2). A distal end 52 of theblade 50 may be disposed near an antinode in order to provide themaximum longitudinal excursion of the distal end. When the transducerassembly is energized, the distal end 52 of the blade 50 may beconfigured to move in the range of, for example, approximately 10 to 500microns peak-to-peak, and preferably in the range of about 30 to 150microns at a predetermined vibrational frequency of 55 kHz, for example.

The blade 50 may comprise features to reduce misting. For example, theblade 50 may comprise a tapered concave surface at the distal end 52, acoating formed at the distal end 52, a lumen fluidically coupled to aspraying mechanism, a material to hold an electric charge, or anycombination thereof.

The blade 50 may be coupled to the ultrasonic transmission waveguide104. The blade 50 and the ultrasonic transmission waveguide 104 asillustrated are formed as a single unit construction from a materialsuitable for transmission of ultrasonic energy. Examples of suchmaterials include Ti6Al4V (an alloy of Titanium including Aluminum andVanadium), Aluminum, Stainless Steel, or other suitable materials.Alternately, the blade 50 may be separable (and of differingcomposition) from the ultrasonic transmission waveguide 104, and coupledby, for example, a stud, weld, glue, quick connect, or other suitableknown methods. The length of the ultrasonic transmission waveguide 104may be substantially equal to an integral number of one-half wavelengths(nλ/2), for example. The ultrasonic transmission waveguide 104 may bepreferably fabricated from a solid core shaft constructed out ofmaterial suitable to propagate ultrasonic energy efficiently, such asthe titanium alloy discussed above (i.e., Ti6Al4V) or any suitablealuminum alloy, or other alloys, for example.

The ultrasonic transmission waveguide 104 comprises a longitudinallyprojecting attachment post 54 at a proximal end to couple to the surface30 of the ultrasonic transmission waveguide 104 by a threaded connectionsuch as the stud 48. In the embodiment illustrated in FIG. 1, theultrasonic transmission waveguide 104 includes a plurality ofstabilizing silicone rings or compliant supports 56 positioned at aplurality of nodes. The silicone rings 56 dampen undesirable vibrationand isolate the ultrasonic energy from an outer sheath 58 assuring theflow of ultrasonic energy in a longitudinal direction to the distal end52 of the blade 50 with maximum efficiency.

As shown in FIG. 1, the outer sheath 58 protects a user of theultrasonic surgical instrument 10, 100 and a patient from the ultrasonicvibrations of the ultrasonic transmission waveguide 104. The sheath 58generally includes a hub 62 and an elongated tubular member 64. Thetubular member 64 is attached to the hub 62 and has an opening extendinglongitudinally therethrough. The sheath 58 is threaded onto the distalend of the housing 16. The ultrasonic transmission waveguide 104 extendsthrough the opening of the tubular member 64 and the silicone rings 56isolate the ultrasonic transmission waveguide 104 from the outer sheath58. The outer sheath 58 may be attached to the waveguide 104 with anisolator pin 112. The hole in the waveguide 104 may occur nominally at adisplacement. The waveguide 104 may screw or snap onto the hand pieceassembly 60 by the stud 48. The flat portions on the hub 62 may allowthe assembly to be torqued to a required level.

The hub 62 of the sheath 58 is preferably constructed from plastic andthe tubular member 64 is fabricated from stainless steel. Alternatively,the ultrasonic transmission waveguide 104 may comprise polymericmaterial surrounding it to isolate it from outside contact.

The distal end of the ultrasonic transmission waveguide 104 may becoupled to the proximal end of the blade 50 by an internal threadedconnection, preferably at or near an antinode. It is contemplated thatthe blade 50 may be attached to the ultrasonic transmission waveguide104 by any suitable means, such as a welded joint or the like. Althoughthe blade 50 may be detachable from the ultrasonic transmissionwaveguide 104, it is also contemplated that the single element endeffector (e.g., the blade 50) and the ultrasonic transmission waveguide104 may be formed as a single unitary piece.

FIG. 1B illustrates one embodiment of an ultrasonic system 1000comprising a multi-element end effector. One embodiment of theultrasonic system 1000 comprises the ultrasonic generator 12 coupled tothe ultrasonic transducer 14 described with reference to FIG. 1A. Theultrasonic transducer 14 is coupled to clamped coagulating shears 1002comprising an instrument housing 1004. The acoustic assembly 18 deliversenergy to the end effector 1016 (FIG. 3B) of the multi-element endassembly 1008 of the multi-element instrument. In order for the acousticassembly 18 to deliver energy to the multi-element end effector ormulti-element end assembly 1008, all components of the acoustic assembly18 must be acoustically coupled to the ultrasonically active portions ofthe clamped coagulating shears 1002. Accordingly, the distal end of theultrasonic transducer 14 may be acoustically coupled at the surface 30to the proximal end of the ultrasonic transmission waveguide 104 by thethreaded connection stud 48.

As previously discussed with reference to the ultrasonic system 10 shownin FIG. 1A, the components of the acoustic assembly 18 are preferablyacoustically tuned such that the length of any assembly is an integralnumber of one-half wavelengths (nλ/2), where the wavelength λ is thewavelength of a pre-selected or operating longitudinal vibration drivefrequency f_(d) of the acoustic assembly 18. The acoustic assembly 18may incorporate any suitable arrangement of acoustic elements.

FIG. 2 illustrates one embodiment of a connection union/joint 70 for anultrasonic instrument. The connection union/joint 70 may be formedbetween the attachment post 54 of the ultrasonic transmission waveguide104 and the surface 30 of the velocity transformer 28 at the distal endof the acoustic assembly 24. The proximal end of the attachment post 54comprises a female threaded substantially cylindrical recess 66 toreceive a portion of the threaded stud 48 therein. The distal end of thevelocity transformer 28 also may comprise a female threadedsubstantially cylindrical recess 68 to receive a portion of the threadedstud 40. The recesses 66, 68 are substantially circumferentially andlongitudinally aligned. In another embodiment (not shown), the stud isan integral component of the end of the ultrasonic transducer. Forexample, the treaded stud and the velocity transformer may be of asingle unit construction with the stud projecting from a distal surfaceof the velocity transformer at the distal end of the acoustic assembly.In this embodiment, the stud is not a separate component and does notrequire a recess in the end of the transducer.

FIG. 3A illustrates an exploded perspective view of one embodiment of asingle element end effector ultrasonic surgical instrument 100. Theultrasonic surgical instrument 100 may be employed with the ultrasonicsystem 10 illustrated in FIG. 1A. However, as described herein, those ofordinary skill in the art will understand that the various embodimentsof the ultrasonic surgical instruments disclosed herein as well as anyequivalent structures thereof could conceivably be effectively used inconnection with other known ultrasonic surgical instruments withoutdeparting from the scope thereof. Thus, the protection afforded to thevarious ultrasonic surgical blade embodiments disclosed herein shouldnot be limited to use only in connection with the exemplary ultrasonicsurgical instrument described above.

In the embodiment illustrated in FIG. 3A, the elongated transmissioncomponent is shown as the ultrasonic waveguide 104 and the end effectoris shown as a single element end effector or blade 50 suitable to cutand/or coagulate tissue. The blade 50 may be symmetrical orasymmetrical.

The length of the blade 50 may be substantially equal to an integralmultiple of one-half system wavelengths (nλ/2). The distal end 52 of theblade 50 may be disposed near an anti-node in order to provide themaximum longitudinal excursion of the distal end 52. When the transducerassembly is energized, the distal end 52 of the blade 50 may beconfigured to move in the range of, for example, approximately 10 to 500microns peak-to-peak, and preferably in the range of about 30 to 150microns at a predetermined vibrational frequency.

The blade 50 may be coupled to the ultrasonic transmission waveguide104. The blade 50 and the ultrasonic transmission guide 104 asillustrated are formed as a single unit of construction from a materialsuitable for transmission of ultrasonic energy such as, for example,Ti6Al4V (an alloy of titanium including aluminum and vanadium),aluminum, stainless steel, other known materials, or combinationsthereof. Alternately, the blade 50 may be separable (and of differingcomposition) from the ultrasonic transmission waveguide 104, and coupledby, for example, a stud, weld, glue, quick connect, or other suitableknown methods. The length of the ultrasonic transmission waveguide 104may be substantially equal to an integral number of one-half systemwavelengths (nλ/2), for example. The ultrasonic transmission waveguide104 also may be preferably fabricated from a solid core shaftconstructed out of material that propagates ultrasonic energyefficiently, such as titanium alloy (e.g., Ti6Al4V) or an aluminumalloy, for example. The ultrasonic transmission waveguide 104 also maybe fabricated from a hollow core shaft constructed out of similarmaterials. The ultrasonic transmission waveguide 104 also may befabricated with a combination solid/hollow core shaft, for example, asolid core shaft with hollow cavities positioned at various locationsalong the length of the shaft.

In the embodiment illustrated in FIG. 3A, the ultrasonic transmissionwaveguide 104 is positioned within the outer sheath 58 by a mountingO-ring 108 and a sealing ring 110. In other embodiments, one or moreadditional dampers or support members (not shown) also may be includedalong the ultrasonic transmission waveguide 104. The ultrasonictransmission waveguide 104 is affixed to the outer sheath 58 by themounting pin 112 that passes through mounting holes 114 in the outersheath 58 and a mounting hole 116 formed in the ultrasonic transmissionwaveguide 104.

FIG. 3B illustrates one embodiment of the clamped coagulating shears1002 comprising a multi-element end effector as shown in FIG. 1B. FIG.3C illustrates a perspective view of the multi-element end effector asshown in FIGS. 1B and 3B. With reference to FIGS. 1B, 3B and 3C, theclamped coagulating shears 1002 may be preferably attached to andremoved from the acoustic assembly 18 as a unit. The proximal end of theclamped coagulating shears 1002 preferably acoustically couples to thedistal surface 30 of the acoustic assembly 18. The clamped coagulatingshears 1002 may be coupled to the acoustic assembly 18 by any suitablemeans.

The clamped coagulating shears 1002 preferably includes an instrumenthousing 1004 and an elongated member 1006. The elongated member 1006 maybe selectively rotated with respect to the instrument housing 1004. Theinstrument housing 1004 includes a pivoting handle portion 1028 and afixed handle portion 1029.

An indexing mechanism (not shown) is disposed within a cavity of theinstrument housing 1004. The indexing mechanism is preferably coupled orattached on an inner tube 1014 to translate movement of the pivotinghandle portion 1028 to linear motion of the inner tube 1014 to open andclose the multi-element end assembly 1008. When the pivoting handleportion 1028 is moved toward the fixed handle portion 1029, the indexingmechanism slide the inner tube 1014 rearward to pivot the multi-elementend assembly 1008 into a closed position. The movement of the pivotinghandle portion 1028 in the opposite direction slides the indexingmechanism to displace the inner tube 1014 in the opposite direction,i.e., forwardly, and hence pivot the multi-element end assembly 1008into its open position in the direction indicated by arrow 1020 as shownin FIG. 3B.

The pivoting handle portion 1028 includes a thumb loop 1030. A pivot pin1032 is disposed through a first hole of the pivoting handle portion1028 to allow pivoting as shown by arrow 1034 in FIG. 3B. As the thumbloop 1030 of the pivoting handle portion 1028 is moved in the directionof arrow 1034, away from the instrument housing 1004, the inner tube1014 slides rearward to pivot the multi-element end assembly 1008 into aclosed position.

The elongated member 1006 of the clamped coagulating shears 1002 extendsfrom the instrument housing 1004. The elongated member 1006 preferablyincludes an outer member or outer tube 1012, an inner member or innertube 1014, and a transmission component or ultrasonic transmissionwaveguide 104.

The multi-element end effector or multi-element end assembly 1008includes a clamp arm assembly 1018, a tissue pad 1036, and an ultrasonicblade 1016. The clamp arm assembly 1018 is pivotally mounted about apivot pin (not shown) to rotate in the direction indicated by arrow1038. The ultrasonic blade 1016 comprises a tapered concave surface 1040extending inwardly into the blade body.

The ultrasonic surgical instrument 100 and the clamped coagulatingshears 1002 may be sterilized by methods known in the art such as, forexample, gamma radiation sterilization, Ethylene Oxide processes,autoclaving, soaking in sterilization liquid, or other known processes.In the embodiment illustrated in FIGS. 1A and 3A, an ultrasonictransmission assembly 102 of the surgical instrument 100 includes thesingle element ultrasonically actuated end effector or blade 50 coupledto the ultrasonic transmission waveguide 104. The blade 50 and theultrasonic transmission waveguide 104 are illustrated as a single unitconstruction from a material suitable for transmission of ultrasonicenergy as previously discussed (e.g., Ti6Al4V, Aluminum, StainlessSteel, or other known materials). Alternately, the blade 50 may beseparable (and of differing composition) from the ultrasonictransmission waveguide 104, and coupled by, for example, a stud, weld,glue, quick connect, or other known methods. In the embodimentillustrated in FIGS. 1B and 3B, the ultrasonic transmission assembly1024 of the clamped coagulating shears 1002 includes the multi-elementend assembly 1008 coupled to the ultrasonic transmission waveguide 104.The length of the ultrasonic transmission waveguide 104 may besubstantially equal to an integral number of one-half system wavelengths(nλ/2), for example. The ultrasonic transmission waveguide 104 may bepreferably fabricated from a solid core shaft constructed out ofmaterial that propagates ultrasonic energy efficiently, such as titaniumalloy (i.e., Ti6Al4V) or an aluminum alloy, for example.

FIGS. 4-22 illustrate various embodiments of ultrasonic blades, whichmay be considered different embodiments of the single element endeffector or the blade 50 or the ultrasonic blade 1016 of themulti-element end assembly 1008 and are generally well-suited forcutting, coagulating, and reshaping tissue. In addition, these bladescomprise mist reducing features. The ultrasonic blades may be employedin the above-described ultrasonic systems 10, 1000. Those skilled in theart will appreciate that although the various embodiments of theultrasonic blades 50, 1016 are well-suited for cutting, coagulating,reshaping tissue, and reducing the mist associated with the previouslydiscussed functions, these ultrasonic blades are multifunctional and maybe employed in multiple numerous applications.

FIGS. 4-6 illustrate one embodiment of an ultrasonic blade 120. Theultrasonic blade 120 is generally well-suited for cutting, coagulating,and reshaping tissue. The ultrasonic blade 120 may be employed invarious other therapeutic procedures. The ultrasonic blade 120 comprisesmist reducing features as described herein. FIG. 4 is a side view of oneembodiment of the ultrasonic blade 120. FIG. 5 is a cross-sectional viewof one embodiment of the ultrasonic blade 120 taken along line 5-5 inFIG. 4. FIG. 6 is a perspective view of one embodiment of the ultrasonicblade in FIG. 4.

In the embodiment illustrated in FIGS. 4-6, the ultrasonic blade 120comprises a blade body 122 having a proximal end 132 and a distal end134. As shown in the cross-sectional view of FIG. 5, the body 122 mayhave a substantially circular cross section. The blade body 122 mayextend along a longitudinal central axis 127. The blade body 122 maycomprise a tapered concave surface 121 at the distal end 134 of theblade body 122 which may extend inwardly into the blade body 122. Thisinward extension may occur such that the blade body has an inwardlytapered concave shaped tip as opposed to a conventional convex shapedtip that extends outwardly or a flat faced tip. The blade body 122 maycomprise a substantially elongated treatment region 128 and a neck ortransition portion 130 that protrudes from the proximal end 132 of thetreatment region 128. The neck portion 130 may be configured to attachto the ultrasonic transmission waveguide 104 by a stud, weld, glue,quick connect, or other suitable attachment methods, for example. Invarious other embodiments, the ultrasonic blade 120 and the ultrasonictransmission waveguide 104 may be formed as a single unitary body. Ineither configuration, the ultrasonic transmission waveguide 104 may havegain steps to amplify the mechanical vibrations transmitted to theultrasonic blade 120 as is well known in the art. The ultrasonic blade120 is adapted to couple to the ultrasonic transmission waveguide 104,which may be employed with the above-described ultrasonic surgicalsystem 10.

In various embodiments, the tapered concave surface 121 may extendinwardly into the blade body 122 from a first edge 124 which may belocated at the distal end 134 of the blade body 122. As previouslydiscussed, the surface 121 may be substantially concave and may betapered inwardly into the blade body 122. In one embodiment, asillustrated in FIG. 20, the concave surface 121 may comprise a convexportion 123 or “bump” within the concave surface 121. FIG. 20 is a sideview of an ultrasonic blade 720 with the convex portion 123 formedwithin the concave surface 121. For example, the substantially concavesurface may have a convex portion 123 or “bump” extending in a directiondifferent from the inward direction of the extension of the surface 121(see FIG. 20, for example).

The tapered concave surface 121 may be configured to produce asubstantially convergent jet 135 of fluid mist, as shown in FIGS. 14A,B, for example. FIG. 14A is a side view of an ultrasonic bladecomprising a tapered concave blade tip depicting the convergent jet 135of fluid mist emanating from the distal end of the blade 120 indirection A. FIG. 14B is a detail view of the convergent jet 135 offluid mist. The convergent jet 135 may be produced by the taperedconcave shape of distal end 134 of the blade body 122. Fluid droplets139 that collide with the tapered concave shape of the distal end 134 ofthe blade body 122 will tend to converge rather than diverge as thefluid droplets 139 travel away from the distal end 134 of the blade body122 in the direction of arrow A. Generally, when the fluid droplets 139collide with a convex shaped blade tip, the fluid particles 139 tend toproduce a substantially divergent jet of fluid mist 137, as shown inFIG. 13A, B, for example. FIG. 13A is a side view of an ultrasonic blade820 with a convex blade tip depicting a typical divergent jet 137 offluid mist. FIG. 13B is a detail view of the divergent jet 137 of fluidmist. For example, when fluid particles associated with the surgicalsite collide with a convex shaped distal end of a blade body, the fluidmist that emanates from the distal end 134 of the blade body indirection A, tends to produce the divergent jet 137 of fluid mist, asshown in FIG. 13A. This fluid mist may limit the visibility at thesurgical site. As shown in FIG. 14B, the tapered concave surface 121 maycause the fluid droplets moving in direction A to be directed towardsthe longitudinal axis 127 where the fluid droplets 141 may collide andcoalesce, thus increasing droplet size such that the fluid droplets 141may drop out under the influence of gravity.

With reference now back to FIGS. 4-6, in various embodiments, the distalend 134 may comprise a first edge 124. The first edge 124 may form thebase from which the tapered surface 121 extends inwardly into the bladebody 122 in the direction B. The first edge 124 may be formed in avariety of shapes including a circle, an ellipse, a square, a rectangle,a pentagon, a hexagon or any suitable polygon. In one embodiment, asshown in FIGS. 4-6, the tapered concave surface 121 defines a conicalshape extending inwardly in direction B into the blade body 122. Theconical shape may comprise a cone with an apex 126 and a circular base.In other embodiments, the base may be an ellipse, or a polygon (e.g., apyramid) and may also comprise a right cone (e.g., where a line joiningthe apex to the center of the base is at a right angle to the baseplane) or an oblique cone (e.g., where a line joining the apex to thecenter of the base is not at a right angle to the base plane). Thesurface may terminate at the apex 126 within the blade body 122. Theconical shape of the tapered concave surface 121 may be symmetrical orasymmetrical. In the embodiment illustrated in FIGS. 4-6, the conicalshape is symmetric with the apex located substantially along thelongitudinal axis 127. In other embodiments, the conical shape of thetapered concave surface 121 may be asymmetric with the apex 126 locatedbetween an outer edge 159 of the blade body 122 and the longitudinalaxis 127. The tapered concave surface 121 may have a second lengthbetween the first edge 124 and the apex 126. The blade body 122 may havea first length between the proximal end 132 and the distal end 134. Thefirst length may be at least three times the second length such thatvibrations produced along the blade body 122 are substantially uniformto provide substantially even distribution of energy to the tissue.

In various other embodiments, the tapered concave surface 221 of theblade body 122 may define various other symmetrical or asymmetricalshapes. In one embodiment, as shown in FIGS. 7-9, the tapered concavesurface 221 may define a frusto-conical shape. FIG. 7 is a side view ofanother embodiment of the ultrasonic blade 220. FIG. 8 is across-sectional view of the ultrasonic blade 220 taken along line 8-8 inFIG. 7. FIG. 9 is a perspective view of the ultrasonic blade 220 in FIG.7. The frusto-conical shape may extend inwardly into the blade body 122in direction B from the first edge 124. The frusto-conical shape maycomprise all of the characteristics of a cone, as defined above, but mayterminate short of a hypothetical apex of the cone, in other words, thefrusto-conical shape may be a shape similar to a cone but terminating ina plane 227 substantially orthogonal to the longitudinal axis 127 asopposed to a point along or near the longitudinal axis 127 found in acone. The tapered concave surface 221 may terminate prior to reachingthe hypothetical apex within the blade body 122. For example, thefrusto-conical shape may be a cone with a substantially flat top asopposed to a point. In various other embodiments, the frusto-conicalshape may have a rounded top or any other suitable shape for the topportion. In the embodiments illustrated in FIGS. 7-9, the frusto-conicalshape of the tapered concave surface 221 is symmetric with the center131 of the plane 227 located substantially along the longitudinal axis127. In other embodiments, the frusto-conical shape of the taperedconcave surface 221 may be asymmetric with the center 131 of the plane227 located between an outer edge 129 of the blade body 122 and thelongitudinal axis 127.

In another embodiment, as shown in FIGS. 10-12, the ultrasonic blade 320comprises a tapered concave surface 321 defining a partial spheroidextending inwardly into the blade body 122 in the direction B. FIG. 10is a side view of the ultrasonic blade 320. FIG. 11 is a cross-sectionalview of the ultrasonic blade 320 taken along line 11-11 in FIG. 10. FIG.12 is a perspective view of the ultrasonic blade 320 in FIG. 10. Thepartial spheroid may extend inwardly from the first edge 124, or base,into the blade body 122 in the direction of B. A spheroid may be formedwhen an ellipse or circle is rotated about an axis. For example, when acircle is rotated about its axis, a spheroid, commonly referred to inthis case as a sphere, is formed. When the ellipse is rotated about itsmajor axis a prolate spheroid is formed, and when the ellipse is rotatedabout its minor axis an oblate spheroid is formed. The tapered concavesurface 321 may define at least one of a partial sphere, a partialprolate spheroid, or a partial oblate spheroid. The partial spheroid maybe more than half of a spheroid, less than half of a spheroid, orexactly half of a spheroid (e.g., a hemispheroid). The first edge 124may form a circle or an ellipse which has a center 133 that may besubstantially aligned with the longitudinal axis 127.

In at least one embodiment, the blade may comprise a variety of shapes.For example, the blade may be curved. The blade may be curved in anydirection. In addition, the blade may comprise various cross-sections.For example, the blade may comprise a square cross-section. All of theseblade shapes may comprise an axis defined between the proximal end 132and the distal end 134 of the blade.

FIG. 23 is a perspective view of an asymmetric ultrasonic bladecomprising a tapered concave surface extending inwardly into the bladebody. More details regarding curved or asymmetric blades are describedin U.S. Pat. No. 6,283,981, which is incorporated herein by reference.As shown in FIG. 23, the ultrasonic surgical instrument 10 may comprisean ultrasonic blade 920 and a treatment region 960 that includes acurved blade designed to cut and coagulate tissue. The treatment region960 may be curved to provide the surgeon with better access andvisibility. The treatment region 960 may also comprise a tapered concavesurface 921 which may provide a mist reducing feature. As illustrated inFIG. 23, the curved treatment region may be symmetrical about x,z plane,but asymmetrical about x,y plane. The tapered concave surface 921 mayextend inwardly into the blade body 922 from a first edge 924 which mayextend substantially parallel to the perimeter of the blade tip 923. Inother embodiments, the first edge may be a different shape from theperimeter of the blade tip. For example, the first edge may form acircle when the perimeter of the blade tip forms a trapezoid. Theembodiments are not limited in this context.

As previously discussed, in various embodiments, the tapered concavesurface may extend inwardly into the blade body 122 in direction B froma first edge 124 either symmetrically or asymmetrically. This extensionmay occur at or near the longitudinal central axis 127 of the blade body122. For example, with respect to the embodiment illustrated in FIGS.4-6, the surface may extend symmetrically to form or define a right coneor asymmetrically to form or define an oblique cone. FIG. 21 is a sideview of an ultrasonic blade 820 with a tapered concave surface 821extending inwardly into the blade body 122 asymmetrically alongdirection B. FIG. 22 is a cross-sectional view of the ultrasonic blade820 taken along line 22-22 in FIG. 21. As shown in FIG. 21, the taperedconcave surface 821 extends inwardly from the distal end 134 of theblade 820 to the proximal end 132 of the blade 820 to form asubstantially oblique cone. The oblique cone may be formedasymmetrically about the longitudinal axis 127. For example, the apex826 of the oblique cone may be offset from the center of thelongitudinal axis 127 or the center 143 of the geometric shape formed bythe first edge 124. The surface may form any geometrical shape, whichmay be formed asymmetrically within the blade body.

In various embodiments, as shown in FIGS. 15A-D, at least a portion 129of the blade body 122 may comprise a layer of material 150 to minimizethe divergent jet 137 of fluid mist (FIGS. 13A, B) associated with theultrasonic blade 420. FIG. 15A is a side view of an ultrasonic blade 420with at least a portion 129 of the ultrasonic blade 420 comprising atleast one layer of the material 150 formed thereon. FIG. 15B iscross-sectional view of the ultrasonic blade 420 taken along line15B-15B in FIG. 15A. FIG. 15C is a detailed view of the ultrasonic blade420 of FIG. 15A. The coated portion 129 of the blade body 122 may belocated at the distal end 134 of the ultrasonic blade 420. The coatedportion 129 of the blade body 122 may comprise at least one layer of amaterial 150 which acts to globulize fluid particles 152 when theycontact the coated portion 129 of the blade body 122. To globulizerefers to creating globules or forming droplets of fluid. The material150 may have properties which cause the material 150 to repel fluid. Forexample, the material 150 may be hydrophobic and thus repel fluid whichmay include irrigation saline, interstitial fluid, blood plasma and acell.

The globulization of the fluid may be caused by differences between thesurface tension of the material 150 and the surface tension of the fluidin contact with the material 150. The material 150 may have a surfacetension which is less than the surface tension of the fluid which maycause the fluid to globulize on the surface of the material 150. A fluidmay form globules or “beads” on surfaces coated with a material wherethe surface tension of the material 150 on the surface 156 is less thanthe surface tension of the fluid. The formation of globules may preventthe “wetting” or formation of a layer of fluid spreading over thesurface of the coated portion 129 of the blade body 122. The globules152 may be pushed off of the blade body 122 through the vibrating motionof the end effector 50 unlike a layer of fluid which may have to beatomized from the surface thus causing a mist to form. The effects ofthe differences between the surface tension of the material 150 and thesurface tension of the fluid may be illustrated in terms of a contactangle formed between a fluid interface and a surface.

FIG. 15D illustrates a contact angle 156 formed between a fluidinterface 157 and a surface 158 of the ultrasonic blade 122 of FIG. 15A.As shown in FIG. 15D, the contact angle 156 is the angle at which thefluid interface 157 meets the surface 158 of the material 150. Thecontact angle 156 is specific for any given system and is determined bythe interactions across the three interfaces. For clarity, the conceptis illustrated with a small liquid droplet resting on a flat horizontalsolid surface. On extremely hydrophilic surfaces, a water droplet willcompletely spread (an effective contact angle of 0°). This occurs forsurfaces that have a large affinity for water (including materials thatabsorb water). On many hydrophilic surfaces, water droplets will exhibitcontact angles of 10° to 30°, for example. On highly hydrophobicsurfaces, which are incompatible with water, one may observe a largecontact angle (70° to 90°). Some surfaces have water contact angles ashigh as 150° or even nearly 180°. On these surfaces, water dropletssimply rest on the surface, without actually wetting the surface to anysignificant extent, for example. These surfaces are termedsuperhydrophobic and can be obtained on fluorinated surfaces(TEFLON®-like coatings) that have been appropriately micropatterned. Thecontact angle 156 thus directly provides information on the interactionenergy between the surface 156 of the material 150 and the fluid.

In various embodiments, the surface 158 of the material 150 may behydrophobic or superhydrophobic. The first material 150 may comprise anyone of polytetrafluoroethylene (TEFLON®), polypropylene, polyethylene,waxes, polycaprolactone, any combination thereof, or any other suitablehydrophobic or superhydrophobic material. For example, the firstmaterial 150 may comprise at least one of a polypropylene waxhydrocarbon mixture or TEFLON®. The first material 150 may be applied tothe surface through a variety of coating techniques including dipping,spraying, brushing, drying, melting, sintering, fused curing, and anyother suitable method for applying hydrophobic materials. Other methodsfor applying hydrophobic materials may include material depositiontechniques that are well known in the art. More details regardinghydrophobic and superhydrophobic materials and methods for applyingthose materials to a surface are described by U.S. Pat. No. 7,041,088and U.S. Pat. No. 6,663,941, which are incorporated herein by reference.

In various other embodiments, as shown in FIGS. 16-17, at least aportion of the blade body 122 may be coated with at least two materialswhich may allow an electric charge to be carried by at least one of thematerials. FIG. 16 is a side view of an ultrasonic blade 520 withportions of the blade body 122 coated with more than one material toprovide an electric charge to the distal end 134 of the blade body 122.FIG. 17 is cross-sectional view of the ultrasonic blade 520 taken alongline 17-17 in FIG. 16. At least a first portion 129 of the blade body122 may comprise at least one layer of a first material 160. This firstmaterial 160 may contact at least a portion of a second material 162.The first material 160 may comprise a material suitable to carry anelectric charge. The electric charge carried by the first material 160may be the same as the nominal electric charge carried by the fluid. Thesimilar electric charges may cause the portion 129 of the blade body 122covered with the first material to repel the fluid. For example, if thefirst material 160 has a positive charge and the fluid has a positivecharge, the fluid will be repelled by the first material 160.Accordingly, the first material 160 acts as a hydrophobic surface. Thefirst material 160 may receive its electrical charge carried by wiresfrom an electrical source located at or near the proximal end 132 of theblade body 122. For example, the electrical source may comprise a directcurrent (“DC”) electrical source (e.g., a battery). In anotherembodiment, the electrical source may be located in a differentlocation. The wires may be provided within a bore formed in theultrasonic blade 520 or maybe provided along the outside of theultrasonic blade 520 within a channel or conduit. The misting effect maybe reduced because the fluid is repelled from the surface of the firstmaterial 160. Accordingly, there is minimal fluid on the surface of theblade body 122 to be atomized by the ultrasonically activated blade 520.

At least a second portion of the blade body 122 comprises at least onelayer of a second material 162. The second material 162 may comprise anelectrically insulative material. The second material 162 may be locatedbetween the first material 160 and the blade body 122. The secondmaterial 162 may insulate the blade 520, and the blade body 122, fromelectrical charges. The second material 162 may be an electret materialwhich may be made from silicon dioxide, fluoropolymer, polypropylene orany other suitable material. These materials may hold a constant or slowdecaying charge. The first material 160 may be a metallic layer or avapor deposited layer acting as a floating conductor wherein wires maynot be required to convey a charge to the second material 162 from anelectrical source.

In another embodiment, the electric charge carried by the first material160 may be the opposite polarity as the nominal electric charge carriedby the fluid. The opposite electric charges may cause the portion 129 ofthe blade body 122 covered with the first material to attract the fluid.For example, if the first material 160 has a negative charge and thefluid has a positive charge, the fluid will be attracted by the firstmaterial 160. Accordingly, the first material 160 acts as a hydrophilicsurface. Accordingly, electric charge on the coating materials may beselected such that they exhibit opposite charges to that of the fluid tocreate attraction rather than repulsion between the blade body 122 andthe fluid. This may enable surgical “smoke” or mist to globulize as itcollects on the surface of the blade body 122. In addition, thistechnique may be employed to attract other materials or constituents,such as, drug molecules, fibrin, and natural adhesives to the treatmentsite. These other materials or constituents may be introduced in aliquid suspension. The difference in charges between the blade body 12ad the fluid would act to concentrate these other materials orconstituents in the vicinity of the distal end of the blade body 122.

In various embodiments, as shown in FIGS. 18-19, a blade 620 maycomprise a bore 180 (e.g., a lumen). FIG. 18 is a side view of theultrasonic blade 620 with a longitudinally extending bore 180. FIG. 19is cross-sectional view of the ultrasonic blade 620 taken along line19-19 in FIG. 18. The bore 180 may extend longitudinally along thelongitudinal axis 127, or, in certain embodiments, the bore may extendin a different direction. The bore 180 may be formed within the blade620. The ultrasonic blade 620 may be configured to emit a spray via thebore 180 in a direction indicated by arrow 640 at the distal end 134 ofthe blade 620. The spray may emanate from a spray source 161 located ator near the proximal end 132 of the blade 620 and travel in the flowdirection 640. The flow direction 640 may be from the proximal end 132to the distal end of the blade 620. In another embodiment, the spraysource 161 may be found in other locations. The spray emanating from thedistal end 134 of the blade 620 may substantially prevent fluid fromcontacting the distal end 134 of the blade 620. This prevention ofcontact may reduce the mist as a layer of fluid may not be present onthe blade 620 for atomization. The spray may comprise a gas. Forexample, the gas may be carbon dioxide, air or some other suitable gas.

The ultrasonic blade 120 comprises a treatment region 128 that issuitable to effect tissue, such as, for example, cut, coagulate,reshape, scrape, and remove tissue. A distal end 134 of the treatmentregion 128 may also comprise a tip with a cutting edge. Additionalcutting edges may be positioned laterally along both sides of thetreatment region 128. In one embodiment, the cutting edges extend fromthe proximal end 132 to the distal end 134 of the treatment region 128.

The ultrasonic blades as discussed herein may be fabricated from amaterial suitable for transmission of ultrasonic energy such as, forexample, Ti6Al4V, Aluminum, Stainless Steel, or other known materials.The ultrasonic blade may be used in a single-element end effector (e.g.,a scalpel, hook, or ball coagulator) as discussed with reference toultrasonic system 10 and FIGS. 1A, 2 and 3A, or a multiple-element endeffector (e.g., a clamping coagulating shears) as discussed withreference to ultrasonic system 1000 and FIGS. 1B, 3B, and 3C, forexample.

The devices disclosed herein can be designed to be disposed of after asingle use, or they can be designed to be used multiple times. In eithercase, however, the device can be reconditioned for reuse after at leastone use. Reconditioning can include any combination of the steps ofdisassembly of the device, followed by cleaning or replacement ofparticular pieces, and subsequent reassembly. In particular, the devicecan be disassembled, and any number of the particular pieces or parts ofthe device can be selectively replaced or removed in any combination.Upon cleaning and/or replacement of particular parts, the device can bereassembled for subsequent use either at a reconditioning facility, orby a surgical team immediately prior to a surgical procedure. Thoseskilled in the art will appreciate that reconditioning of a device canutilize a variety of techniques for disassembly, cleaning/replacement,and reassembly. Use of such techniques, and the resulting reconditioneddevice, are all within the scope of the present application.

Preferably, the various embodiments described herein will be processedbefore surgery. First, a new or used instrument is obtained and ifnecessary cleaned. The instrument can then be sterilized. In onesterilization technique, the instrument is placed in a closed and sealedcontainer, such as a plastic or TYVEK® bag. The container and instrumentare then placed in a field of radiation that can penetrate thecontainer, such as gamma radiation, x-rays, or high-energy electrons.The radiation kills bacteria on the instrument and in the container. Thesterilized instrument can then be stored in the sterile container. Thesealed container keeps the instrument sterile until it is opened in themedical facility.

It is preferred that the device is sterilized. This can be done by anynumber of ways known to those skilled in the art including beta or gammaradiation, ethylene oxide, steam.

Although various embodiments have been described herein, manymodifications and variations to those embodiments may be implemented.For example, different types of end effectors may be employed. Inaddition, combinations of the described embodiments may be used. Forexample, a concave blade tip may be coated with a hydrophobic material.Also, where materials are disclosed for certain components, othermaterials may be used. The foregoing description and following claimsare intended to cover all such modification and variations.

Any patent, publication, or other disclosure material, in whole or inpart, that is said to be incorporated by reference herein isincorporated herein only to the extent that the incorporated materialsdoes not conflict with existing definitions, statements, or otherdisclosure material set forth in this disclosure. As such, and to theextent necessary, the disclosure as explicitly set forth hereinsupersedes any conflicting material incorporated herein by reference.Any material, or portion thereof, that is said to be incorporated byreference herein, but which conflicts with existing definitions,statements, or other disclosure material set forth herein will only beincorporated to the extent that no conflict arises between thatincorporated material and the existing disclosure material.

What is claimed is:
 1. An ultrasonic surgical blade for the treatment oftissue, comprising: a solid blade body defining an axis, the solid bladebody comprising: a first length; a proximal end; and a distal end,wherein the solid blade body is configured to acoustically couple to anultrasonic transducer; a treatment region; a first edge at the distalend of the solid blade body; and an inner concave surface, comprising: acavity extending proximally from the distal end of the solid blade bodyalong the axis, wherein the cavity terminates at a proximal end of theinner concave surface, wherein the cavity comprises a second lengthbetween the first edge and the proximal end, wherein the first length issubstantially longer than the second length, wherein the cavity issubstantially concave and comprises a convex portion, and wherein theconvex portion comprises a partial ellipsoid surface.
 2. The ultrasonicsurgical blade of claim 1, wherein the inner concave surface isconfigured to cause fluid droplets to converge along the axis at a pointbeyond the distal end of the solid blade body.
 3. The ultrasonicsurgical blade of claim 1, wherein the cavity terminates at a planesubstantially orthogonal to the axis.
 4. The ultrasonic surgical bladeof claim 1, wherein the treatment region comprises a curved blade. 5.The ultrasonic surgical blade of claim 1, wherein the treatment regioncomprises at least one coagulating edge.
 6. The ultrasonic surgicalblade of claim 1, wherein the inner concave surface is asymmetric. 7.The ultrasonic surgical blade of claim 1, wherein the treatment regioncomprises at least one cutting edge.
 8. The ultrasonic surgical blade ofclaim 1, wherein the solid blade body further comprises an apex.
 9. Theultrasonic surgical blade of claim 8, wherein the inner concave surfaceextends inwardly toward the apex.
 10. The ultrasonic surgical blade ofclaim 9, wherein the inner concave surface terminates at the apex withinthe solid blade body.
 11. The ultrasonic surgical blade of claim 1,wherein the first edge forms a base of the inner concave surface. 12.The ultrasonic surgical blade of claim 1, wherein the inner concavesurface terminates at the partial ellipsoid surface.